1. Field Of The Invention
This invention relates to an apparatus and a method for the controlled exposure and processing of a sheet, for example a photosensitive sheet.
2. Description Of The Prior Art
In U.S. Pat. Nos. 3,801,321 and 3,893,860 there are described sensitized materials, such as photosensitive paper, which may be selectively exposed by appropriate actinic radiation to form latent images thereon and which images may be developed by subjecting the materials to a specified temperature for a controlled period of time. Typically, a sheet of a sensitive material is withdrawn from a roll, metered to an exposure station, severed from the roll either prior to or after exposure and exposed for a suitable period. After exposure, the exposed sheet is directed into a processing or developing station which may illustratively take the form of a heating assembly. It is known to provide the necessary heat to develop the sheet by feeding the sheet upon a rotating and heated drum so that, through contact of the sheet with the drum, sufficient heat is transferred to the sheet to develop the image thereon. The time for heat development of the sheet is generally an important factor in the processing of the photosensitive materials to which reference has been made. In this regard, processing of any portion of a sheet is considered to commence when such portion has been placed into contact with the heated drum. To provide for uniform processing of a sheet on a drum, the drum is rotated at a carefully controlled rate and sheet entrance and exit devices are arranged about the drum so that the first portion of a sheet is the first to contact and to be removed from the drum with succeeding portions of the sheet following in turn. Thus each portion of the sheet is in contact with the drum for the same total time as any other portion.
In providing for an apparatus to make prints it is desirable that the apparatus be compact and have the capability of providing successive finished prints with a minimum of waiting time between them. In U.S. Pat. No. 3,640,198 it is recognized that the time between successive prints may be reduced by varying the speeds at which the sheet is moved through the apparatus. Thus the sheet may be removed from the exposure station into the processing station at a relatively high rate, slowed to a relatively low rate while in the processor and accelerated to a relatively high rate during removal from the processor. While this apparatus works well and may indeed reduce access time between successive prints an additional motor or some other means for varying speed must be provided to permit the sheet to be moved through the processor at more than one speed.
It is therefore an object of this invention to provide an apparatus and method for making prints which features a relatively low access time between successive prints without the need for rotating a processing drum at at least two differing speeds.
It is a further object of the invention to provide an apparatus and method for making prints which permits such apparatus to be of relatively small size.